/*****************************************************************************
* auth.c - Network Authentication and Phase Control program file.
*
* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
* Copyright (c) 1997 by Global Election Systems Inc.  All rights reserved.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice and the following disclaimer are included verbatim in any
* distributions. No written agreement, license, or royalty fee is required
* for any of the authorized uses.
*
* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
* REVISION HISTORY
*
* 03-01-01 Marc Boucher <marc@mbsi.ca>
*   Ported to lwIP.
* 97-12-08 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
*   Ported from public pppd code.
*****************************************************************************/
/*
 * auth.c - PPP authentication and phase control.
 *
 * Copyright (c) 1993 The Australian National University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the Australian National University.  The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include "ppp.h"
#if PPP_SUPPORT > 0
#include "fsm.h"
#include "lcp.h"
#include "pap.h"
#include "chap.h"
#include "auth.h"
#include "ipcp.h"

#if CBCP_SUPPORT > 0
#include "cbcp.h"
#endif

#include "pppdebug.h"


/*************************/
/*** LOCAL DEFINITIONS ***/
/*************************/

/* Bits in auth_pending[] */
#define PAP_WITHPEER    1
#define PAP_PEER    2
#define CHAP_WITHPEER   4
#define CHAP_PEER   8



/************************/
/*** LOCAL DATA TYPES ***/
/************************/
/* Used for storing a sequence of words.  Usually malloced. */
struct wordlist
{
        struct wordlist *next;
        char        word[1];
};



/***********************************/
/*** LOCAL FUNCTION DECLARATIONS ***/
/***********************************/
extern char *crypt (const char *, const char *);

/* Prototypes for procedures local to this file. */

static void network_phase (int);
static void check_idle (void *);
static void connect_time_expired (void *);
#if 0
static int  login (char *, char *, char **, int *);
#endif
static void logout (void);
static int  null_login (int);
static int  get_pap_passwd (int, char *, char *);
static int  have_pap_secret (void);
static int  have_chap_secret (char *, char *, u32_t);
static int  ip_addr_check (u32_t, struct wordlist *);
#if 0 /* PAP_SUPPORT > 0 || CHAP_SUPPORT > 0 */
static void set_allowed_addrs(int unit, struct wordlist *addrs);
static void free_wordlist (struct wordlist *);
#endif
#if CBCP_SUPPORT > 0
static void callback_phase (int);
#endif


/******************************/
/*** PUBLIC DATA STRUCTURES ***/
/******************************/


/*****************************/
/*** LOCAL DATA STRUCTURES ***/
/*****************************/
#if PAP_SUPPORT > 0 || CHAP_SUPPORT > 0
/* The name by which the peer authenticated itself to us. */
static char peer_authname[MAXNAMELEN];
#endif

/* Records which authentication operations haven't completed yet. */
static int auth_pending[NUM_PPP];

/* Set if we have successfully called login() */
static int logged_in;

/* Set if we have run the /etc/ppp/auth-up script. */
static int did_authup;

/* List of addresses which the peer may use. */
static struct wordlist *addresses[NUM_PPP];

/* Number of network protocols which we have opened. */
static int num_np_open;

/* Number of network protocols which have come up. */
static int num_np_up;

#if PAP_SUPPORT > 0 || CHAP_SUPPORT > 0
/* Set if we got the contents of passwd[] from the pap-secrets file. */
static int passwd_from_file;
#endif



/***********************************/
/*** PUBLIC FUNCTION DEFINITIONS ***/
/***********************************/
/*
 * An Open on LCP has requested a change from Dead to Establish phase.
 * Do what's necessary to bring the physical layer up.
 */
void link_required(int unit)
{
        AUTHDEBUG((LOG_INFO, "link_required: %d\n", unit));
}

/*
 * LCP has terminated the link; go to the Dead phase and take the
 * physical layer down.
 */
void link_terminated(int unit)
{
        AUTHDEBUG((LOG_INFO, "link_terminated: %d\n", unit));

        if (lcp_phase[unit] == PHASE_DEAD)
                return;
        if (logged_in)
                logout();
        lcp_phase[unit] = PHASE_DEAD;
        AUTHDEBUG((LOG_NOTICE, "Connection terminated.\n"));
        pppMainWakeup(unit);
}

/*
 * LCP has gone down; it will either die or try to re-establish.
 */
void link_down(int unit)
{
        int i;
        struct protent *protp;

        AUTHDEBUG((LOG_INFO, "link_down: %d\n", unit));
        if (did_authup) {
                /* XXX Do link down processing. */
                did_authup = 0;
        }
        for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
                if (!protp->enabled_flag)
                        continue;
                if (protp->protocol != PPP_LCP && protp->lowerdown != NULL)
                        (*protp->lowerdown)(unit);
                if (protp->protocol < 0xC000 && protp->close != NULL)
                        (*protp->close)(unit, "LCP down");
        }
        num_np_open = 0;
        num_np_up = 0;
        if (lcp_phase[unit] != PHASE_DEAD)
                lcp_phase[unit] = PHASE_TERMINATE;
        pppMainWakeup(unit);
}

/*
 * The link is established.
 * Proceed to the Dead, Authenticate or Network phase as appropriate.
 */
void link_established(int unit)
{
        int auth;
        int i;
        struct protent *protp;
        lcp_options *wo = &lcp_wantoptions[unit];
        lcp_options *go = &lcp_gotoptions[unit];
#if PAP_SUPPORT > 0 || CHAP_SUPPORT > 0
        lcp_options *ho = &lcp_hisoptions[unit];
#endif

        AUTHDEBUG((LOG_INFO, "link_established: %d\n", unit));
        /*
         * Tell higher-level protocols that LCP is up.
         */
        for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i)
                if (protp->protocol != PPP_LCP && protp->enabled_flag
                                && protp->lowerup != NULL)
                        (*protp->lowerup)(unit);

        if (ppp_settings.auth_required && !(go->neg_chap || go->neg_upap)) {
                /*
                 * We wanted the peer to authenticate itself, and it refused:
                 * treat it as though it authenticated with PAP using a username
                 * of "" and a password of "".  If that's not OK, boot it out.
                 */
                if (!wo->neg_upap || !null_login(unit)) {
                        AUTHDEBUG((LOG_WARNING, "peer refused to authenticate\n"));
                        lcp_close(unit, "peer refused to authenticate");
                        return;
                }
        }

        lcp_phase[unit] = PHASE_AUTHENTICATE;
        auth = 0;
#if CHAP_SUPPORT > 0
        if (go->neg_chap) {
                ChapAuthPeer(unit, ppp_settings.our_name, go->chap_mdtype);
                auth |= CHAP_PEER;
        }
#endif
#if PAP_SUPPORT > 0 && CHAP_SUPPORT > 0
        else
#endif
#if PAP_SUPPORT > 0
                if (go->neg_upap) {
                        upap_authpeer(unit);
                        auth |= PAP_PEER;
                }
#endif
#if CHAP_SUPPORT > 0
        if (ho->neg_chap) {
                ChapAuthWithPeer(unit, ppp_settings.user, ho->chap_mdtype);
                auth |= CHAP_WITHPEER;
        }
#endif
#if PAP_SUPPORT > 0 && CHAP_SUPPORT > 0
        else
#endif
#if PAP_SUPPORT > 0
                if (ho->neg_upap) {
                        if (ppp_settings.passwd[0] == 0) {
                                passwd_from_file = 1;
                                if (!get_pap_passwd(unit, ppp_settings.user, ppp_settings.passwd))
                                        AUTHDEBUG((LOG_ERR, "No secret found for PAP login\n"));
                        }
                        upap_authwithpeer(unit, ppp_settings.user, ppp_settings.passwd);
                        auth |= PAP_WITHPEER;
                }
#endif
        auth_pending[unit] = auth;

        if (!auth)
                network_phase(unit);
}


/*
 * The peer has failed to authenticate himself using `protocol'.
 */
void auth_peer_fail(int unit, u16_t protocol)
{
        AUTHDEBUG((LOG_INFO, "auth_peer_fail: %d proto=%X\n", unit, protocol));
        /*
         * Authentication failure: take the link down
         */
        lcp_close(unit, "Authentication failed");
}


#if PAP_SUPPORT > 0 || CHAP_SUPPORT > 0
/*
 * The peer has been successfully authenticated using `protocol'.
 */
void auth_peer_success(int unit, u16_t protocol, char *name, int namelen)
{
        int pbit;

        AUTHDEBUG((LOG_INFO, "auth_peer_success: %d proto=%X\n", unit, protocol));
        switch (protocol) {
        case PPP_CHAP:
                pbit = CHAP_PEER;
                break;
        case PPP_PAP:
                pbit = PAP_PEER;
                break;
        default:
                AUTHDEBUG((LOG_WARNING, "auth_peer_success: unknown protocol %x\n",
                           protocol));
                return;
        }

        /*
         * Save the authenticated name of the peer for later.
         */
        if (namelen > sizeof(peer_authname) - 1)
                namelen = sizeof(peer_authname) - 1;
        BCOPY(name, peer_authname, namelen);
        peer_authname[namelen] = 0;

        /*
         * If there is no more authentication still to be done,
         * proceed to the network (or callback) phase.
         */
        if ((auth_pending[unit] &= ~pbit) == 0)
                network_phase(unit);
}

/*
 * We have failed to authenticate ourselves to the peer using `protocol'.
 */
void auth_withpeer_fail(int unit, u16_t protocol)
{
        int errCode = PPPERR_AUTHFAIL;

        AUTHDEBUG((LOG_INFO, "auth_withpeer_fail: %d proto=%X\n", unit, protocol));
        if (passwd_from_file)
                BZERO(ppp_settings.passwd, MAXSECRETLEN);
        /*
         * XXX Warning: the unit number indicates the interface which is
         * not necessarily the PPP connection.  It works here as long
         * as we are only supporting PPP interfaces.
         */
        pppIOCtl(unit, PPPCTLS_ERRCODE, &errCode);

        /*
         * We've failed to authenticate ourselves to our peer.
         * He'll probably take the link down, and there's not much
         * we can do except wait for that.
         */
}

/*
 * We have successfully authenticated ourselves with the peer using `protocol'.
 */
void auth_withpeer_success(int unit, u16_t protocol)
{
        int pbit;

        AUTHDEBUG((LOG_INFO, "auth_withpeer_success: %d proto=%X\n", unit, protocol));
        switch (protocol) {
        case PPP_CHAP:
                pbit = CHAP_WITHPEER;
                break;
        case PPP_PAP:
                if (passwd_from_file)
                        BZERO(ppp_settings.passwd, MAXSECRETLEN);
                pbit = PAP_WITHPEER;
                break;
        default:
                AUTHDEBUG((LOG_WARNING, "auth_peer_success: unknown protocol %x\n",
                           protocol));
                pbit = 0;
        }

        /*
         * If there is no more authentication still being done,
         * proceed to the network (or callback) phase.
         */
        if ((auth_pending[unit] &= ~pbit) == 0)
                network_phase(unit);
}
#endif


/*
 * np_up - a network protocol has come up.
 */
void np_up(int unit, u16_t proto)
{
        AUTHDEBUG((LOG_INFO, "np_up: %d proto=%X\n", unit, proto));
        if (num_np_up == 0) {
                AUTHDEBUG((LOG_INFO, "np_up: maxconnect=%d idle_time_limit=%d\n",ppp_settings.maxconnect,ppp_settings.idle_time_limit));
                /*
                 * At this point we consider that the link has come up successfully.
                 */
                if (ppp_settings.idle_time_limit > 0)
                        TIMEOUT(check_idle, NULL, ppp_settings.idle_time_limit);

                /*
                 * Set a timeout to close the connection once the maximum
                 * connect time has expired.
                 */
                if (ppp_settings.maxconnect > 0)
                        TIMEOUT(connect_time_expired, 0, ppp_settings.maxconnect);
        }
        ++num_np_up;
}

/*
 * np_down - a network protocol has gone down.
 */
void np_down(int unit, u16_t proto)
{
        AUTHDEBUG((LOG_INFO, "np_down: %d proto=%X\n", unit, proto));
        if (--num_np_up == 0 && ppp_settings.idle_time_limit > 0) {
                UNTIMEOUT(check_idle, NULL);
        }
}

/*
 * np_finished - a network protocol has finished using the link.
 */
void np_finished(int unit, u16_t proto)
{
        AUTHDEBUG((LOG_INFO, "np_finished: %d proto=%X\n", unit, proto));
        if (--num_np_open <= 0) {
                /* no further use for the link: shut up shop. */
                lcp_close(0, "No network protocols running");
        }
}

/*
 * auth_reset - called when LCP is starting negotiations to recheck
 * authentication options, i.e. whether we have appropriate secrets
 * to use for authenticating ourselves and/or the peer.
 */
void auth_reset(int unit)
{
        lcp_options *go = &lcp_gotoptions[unit];
        lcp_options *ao = &lcp_allowoptions[0];
        ipcp_options *ipwo = &ipcp_wantoptions[0];
        u32_t remote;

        AUTHDEBUG((LOG_INFO, "auth_reset: %d\n", unit));
        ao->neg_upap = !ppp_settings.refuse_pap && (ppp_settings.passwd[0] != 0 || get_pap_passwd(unit, NULL, NULL));
        ao->neg_chap = !ppp_settings.refuse_chap && ppp_settings.passwd[0] != 0 /*have_chap_secret(ppp_settings.user, ppp_settings.remote_name, (u32_t)0)*/;

        if (go->neg_upap && !have_pap_secret())
                go->neg_upap = 0;
        if (go->neg_chap) {
                remote = ipwo->accept_remote? 0: ipwo->hisaddr;
                if (!have_chap_secret(ppp_settings.remote_name, ppp_settings.our_name, remote))
                        go->neg_chap = 0;
        }
}


#if PAP_SUPPORT > 0
/*
 * check_passwd - Check the user name and passwd against the PAP secrets
 * file.  If requested, also check against the system password database,
 * and login the user if OK.
 *
 * returns:
 *  UPAP_AUTHNAK: Authentication failed.
 *  UPAP_AUTHACK: Authentication succeeded.
 * In either case, msg points to an appropriate message.
 */
int check_passwd(
        int unit,
        char *auser,
        int userlen,
        char *apasswd,
        int passwdlen,
        char **msg,
        int *msglen
)
{
#if 1
        *msg = (char *) 0;
        return UPAP_AUTHACK;     /* XXX Assume all entries OK. */
#else
        int ret = 0;
        struct wordlist *addrs = NULL;
        char passwd[256], user[256];
        char secret[MAXWORDLEN];
        static u_short attempts = 0;

        /*
        * Make copies of apasswd and auser, then null-terminate them.
        */
        BCOPY(apasswd, passwd, passwdlen);
        passwd[passwdlen] = '\0';
        BCOPY(auser, user, userlen);
        user[userlen] = '\0';
        *msg = (char *) 0;

        /* XXX Validate user name and password. */
        ret = UPAP_AUTHACK;     /* XXX Assume all entries OK. */

        if (ret == UPAP_AUTHNAK) {
                if (*msg == (char *) 0)
                        *msg = "Login incorrect";
                *msglen = strlen(*msg);
                /*
                * Frustrate passwd stealer programs.
                * Allow 10 tries, but start backing off after 3 (stolen from login).
                * On 10'th, drop the connection.
                */
                if (attempts++ >= 10) {
                        AUTHDEBUG((LOG_WARNING, "%d LOGIN FAILURES BY %s\n", attempts, user));
                        /*ppp_panic("Excess Bad Logins");*/
                }
                if (attempts > 3) {
                        sys_msleep((attempts - 3) * 5);
                }
                if (addrs != NULL) {
                        free_wordlist(addrs);
                }
        } else {
                attempts = 0;           /* Reset count */
                if (*msg == (char *) 0)
                        *msg = "Login ok";
                *msglen = strlen(*msg);
                set_allowed_addrs(unit, addrs);
        }

        BZERO(passwd, sizeof(passwd));
        BZERO(secret, sizeof(secret));

        return ret;
#endif
}
#endif


/*
 * auth_ip_addr - check whether the peer is authorized to use
 * a given IP address.  Returns 1 if authorized, 0 otherwise.
 */
int auth_ip_addr(int unit, u32_t addr)
{
        return ip_addr_check(addr, addresses[unit]);
}

/*
 * bad_ip_adrs - return 1 if the IP address is one we don't want
 * to use, such as an address in the loopback net or a multicast address.
 * addr is in network byte order.
 */
int bad_ip_adrs(u32_t addr)
{
        addr = ntohl(addr);
        return (addr >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET
               || IN_MULTICAST(addr) || IN_BADCLASS(addr);
}


#if CHAP_SUPPORT > 0
/*
 * get_secret - open the CHAP secret file and return the secret
 * for authenticating the given client on the given server.
 * (We could be either client or server).
 */
int get_secret(
        int unit,
        char *client,
        char *server,
        char *secret,
        int *secret_len,
        int save_addrs
)
{
#if 1
        int len;
        struct wordlist *addrs;

        addrs = NULL;

        if (!client || !client[0] || strcmp(client, ppp_settings.user)) {
                return 0;
        }

        len = strlen(ppp_settings.passwd);
        if (len > MAXSECRETLEN) {
                AUTHDEBUG((LOG_ERR, "Secret for %s on %s is too long\n", client, server));
                len = MAXSECRETLEN;
        }
        BCOPY(ppp_settings.passwd, secret, len);
        *secret_len = len;

        return 1;
#else
        int ret = 0, len;
        struct wordlist *addrs;
        char secbuf[MAXWORDLEN];

        addrs = NULL;
        secbuf[0] = 0;

        /* XXX Find secret. */
        if (ret < 0)
                return 0;

        if (save_addrs)
                set_allowed_addrs(unit, addrs);

        len = strlen(secbuf);
        if (len > MAXSECRETLEN) {
                AUTHDEBUG((LOG_ERR, "Secret for %s on %s is too long\n", client, server));
                len = MAXSECRETLEN;
        }
        BCOPY(secbuf, secret, len);
        BZERO(secbuf, sizeof(secbuf));
        *secret_len = len;

        return 1;
#endif
}
#endif


#if 0 /* UNUSED */
/*
 * auth_check_options - called to check authentication options.
 */
void auth_check_options(void)
{
        lcp_options *wo = &lcp_wantoptions[0];
        int can_auth;
        ipcp_options *ipwo = &ipcp_wantoptions[0];
        u32_t remote;

        /* Default our_name to hostname, and user to our_name */
        if (ppp_settings.our_name[0] == 0 || ppp_settings.usehostname)
                strcpy(ppp_settings.our_name, ppp_settings.hostname);
        if (ppp_settings.user[0] == 0)
                strcpy(ppp_settings.user, ppp_settings.our_name);

        /* If authentication is required, ask peer for CHAP or PAP. */
        if (ppp_settings.auth_required && !wo->neg_chap && !wo->neg_upap) {
                wo->neg_chap = 1;
                wo->neg_upap = 1;
        }

        /*
         * Check whether we have appropriate secrets to use
         * to authenticate the peer.
         */
        can_auth = wo->neg_upap && have_pap_secret();
        if (!can_auth && wo->neg_chap) {
                remote = ipwo->accept_remote? 0: ipwo->hisaddr;
                can_auth = have_chap_secret(ppp_settings.remote_name, ppp_settings.our_name, remote);
        }

        if (ppp_settings.auth_required && !can_auth) {
                ppp_panic("No auth secret");
        }
}
#endif


/**********************************/
/*** LOCAL FUNCTION DEFINITIONS ***/
/**********************************/
/*
 * Proceed to the network phase.
 */
static void network_phase(int unit)
{
        int i;
        struct protent *protp;
        lcp_options *go = &lcp_gotoptions[unit];

        /*
         * If the peer had to authenticate, run the auth-up script now.
         */
        if ((go->neg_chap || go->neg_upap) && !did_authup) {
                /* XXX Do setup for peer authentication. */
                did_authup = 1;
        }

#if CBCP_SUPPORT > 0
        /*
         * If we negotiated callback, do it now.
         */
        if (go->neg_cbcp) {
                lcp_phase[unit] = PHASE_CALLBACK;
                (*cbcp_protent.open)(unit);
                return;
        }
#endif

        lcp_phase[unit] = PHASE_NETWORK;
        for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i)
                if (protp->protocol < 0xC000 && protp->enabled_flag
                                && protp->open != NULL) {
                        (*protp->open)(unit);
                        if (protp->protocol != PPP_CCP)
                                ++num_np_open;
                }

        if (num_np_open == 0)
                /* nothing to do */
                lcp_close(0, "No network protocols running");
}

/*
 * check_idle - check whether the link has been idle for long
 * enough that we can shut it down.
 */
static void check_idle(void *arg)
{
        struct ppp_idle idle;
        u_short itime;

        (void)arg;
        if (!get_idle_time(0, &idle))
                return;
        itime = LWIP_MIN(idle.xmit_idle, idle.recv_idle);
        if (itime >= ppp_settings.idle_time_limit) {
                /* link is idle: shut it down. */
                AUTHDEBUG((LOG_INFO, "Terminating connection due to lack of activity.\n"));
                lcp_close(0, "Link inactive");
        } else {
                TIMEOUT(check_idle, NULL, ppp_settings.idle_time_limit - itime);
        }
}

/*
 * connect_time_expired - log a message and close the connection.
 */
static void connect_time_expired(void *arg)
{
        (void)arg;

        AUTHDEBUG((LOG_INFO, "Connect time expired\n"));
        lcp_close(0, "Connect time expired");   /* Close connection */
}

#if 0
/*
 * login - Check the user name and password against the system
 * password database, and login the user if OK.
 *
 * returns:
 *  UPAP_AUTHNAK: Login failed.
 *  UPAP_AUTHACK: Login succeeded.
 * In either case, msg points to an appropriate message.
 */
static int login(char *user, char *passwd, char **msg, int *msglen)
{
        /* XXX Fail until we decide that we want to support logins. */
        return (UPAP_AUTHNAK);
}
#endif

/*
 * logout - Logout the user.
 */
static void logout(void)
{
        logged_in = 0;
}


/*
 * null_login - Check if a username of "" and a password of "" are
 * acceptable, and iff so, set the list of acceptable IP addresses
 * and return 1.
 */
static int null_login(int unit)
{
        (void)unit;
        /* XXX Fail until we decide that we want to support logins. */
        return 0;
}


/*
 * get_pap_passwd - get a password for authenticating ourselves with
 * our peer using PAP.  Returns 1 on success, 0 if no suitable password
 * could be found.
 */
static int get_pap_passwd(int unit, char *user, char *passwd)
{
        /* normally we would reject PAP if no password is provided,
           but this causes problems with some providers (like CHT in Taiwan)
           who incorrectly request PAP and expect a bogus/empty password, so
           always provide a default user/passwd of "none"/"none"
        */
        if (user)
                strcpy(user,   "none");
        if (passwd)
                strcpy(passwd, "none");

        return 1;
}


/*
 * have_pap_secret - check whether we have a PAP file with any
 * secrets that we could possibly use for authenticating the peer.
 */
static int have_pap_secret(void)
{
        /* XXX Fail until we set up our passwords. */
        return 0;
}


/*
 * have_chap_secret - check whether we have a CHAP file with a
 * secret that we could possibly use for authenticating `client'
 * on `server'.  Either can be the null string, meaning we don't
 * know the identity yet.
 */
static int have_chap_secret(char *client, char *server, u32_t remote)
{
        (void)client;
        (void)server;
        (void)remote;
        /* XXX Fail until we set up our passwords. */
        return 0;
}


#if 0 /* PAP_SUPPORT > 0 || CHAP_SUPPORT > 0 */
/*
 * set_allowed_addrs() - set the list of allowed addresses.
 */
static void set_allowed_addrs(int unit, struct wordlist *addrs)
{
        if (addresses[unit] != NULL)
                free_wordlist(addresses[unit]);
        addresses[unit] = addrs;

#if 0
        /*
         * If there's only one authorized address we might as well
         * ask our peer for that one right away
         */
        if (addrs != NULL && addrs->next == NULL)
        {
                char *p = addrs->word;
                struct ipcp_options *wo = &ipcp_wantoptions[unit];
                u32_t a;
                struct hostent *hp;

                if (wo->hisaddr == 0 && *p != '!' && *p != '-'
                                && strchr(p, '/') == NULL) {
                        hp = gethostbyname(p);
                        if (hp != NULL && hp->h_addrtype == AF_INET)
                                a = *(u32_t *)hp->h_addr;
                        else
                                a = inet_addr(p);
                        if (a != (u32_t) -1)
                                wo->hisaddr = a;
                }
        }
#endif
}
#endif

static int ip_addr_check(u32_t addr, struct wordlist *addrs)
{

        /* don't allow loopback or multicast address */
        if (bad_ip_adrs(addr))
                return 0;

        if (addrs == NULL)
                return !ppp_settings.auth_required;      /* no addresses authorized */

        /* XXX All other addresses allowed. */
        return 1;
}

#if 0 /* PAP_SUPPORT > 0 || CHAP_SUPPORT */
/*
 * free_wordlist - release memory allocated for a wordlist.
 */
static void free_wordlist(struct wordlist *wp)
{
        struct wordlist *next;

        while (wp != NULL)
        {
                next = wp->next;
                free(wp);
                wp = next;
        }
}
#endif

#endif /* PPP_SUPPORT */
